Nausea and Vomiting

Question 1

Define nausea

Answer 1

Unpleasant feeling of the need to vomit

Question 2

Define vomiting

Answer 2

Explusion of gastric contents through the mouth caused by forceful and sustained contraction of the abdominal muscles and the diaphragm

Question 3

What things can cause vomiting?

Answer 3

Drugs
Biochemical causes
Motion sickness
Sights, smells
Fear, anxiety
Raised ICP
Gag reflex
Gastric stasis/motility
Gastric irritation 
Visceral stretching (MI, bowel, liver capsule, bladder)

Question 4

What is the chemoreceptor trigger zone (CTZ)?

Answer 4

Area that receives inputs from drugs or hormones, and communicates with other structures in the vomiting centre to initiate vomiting

Question 5

Where is the CTZ found?

Answer 5

Area postrema, (on floor of the fourth ventricle and is outside of the blood–brain barrier) in the medulla oblongata

Question 6

What part of the brain communicates with the vomiting centre to produce motion sickness?

Answer 6

Vestibulocochlear organs

Question 7

What part of the brain communicates with the vomiting centre to produce nausea/vomiting due to sights/smells/anxiety/raised ICP?

Answer 7

Cerebral cortex

Question 8

What nerves communicate with the GI tract to cause nausea/vomiting?

Answer 8

Vagus, splanchnic and sympathetic NS

Question 9

What nerve is involved in the gag reflex?

Answer 9

Glossopharyngeal

Question 10

What are the two main parts of the brain that are involved in vomiting?

Answer 10

CTZ and vomiting centre
CTZ - activated by drugs/hormones + when activated sends signals to vomiting centres
Vomiting centre - causes smooth muscle contractions in GIT to cause emesis

Question 11

What things may activate the vomiting centre?

Answer 11

Raised ICP
Motion, sights/smells
Pharynx
Visceral stretching (e.g. liver capsule, MI…)